fix(desktop): tighten compact conversation layout

.qwen/e2e-tests/electron-desktop/compact-dense-conversation.md

@@ -0,0 +1,60 @@
+# Compact Dense Conversation
+
+- Slice date: 2026-04-26
+- Executable harness: `packages/desktop/scripts/e2e-cdp-smoke.mjs`
+- Command:
+  `cd packages/desktop && npm run e2e:cdp`
+- Result: pass
+- Artifact directory:
+  `.qwen/e2e-tests/electron-desktop/artifacts/2026-04-25T18-31-38-896Z/`
+
+## Scenario
+
+1. Launch the real Electron app with isolated HOME, runtime, user-data, and a
+   fake dirty Git workspace.
+2. Open the fake project through the desktop directory picker path.
+3. Send the first composer prompt and approve the fake command request.
+4. Wait for the fake ACP assistant response with dense repeated file
+   references.
+5. Assert the default-width assistant actions and dense file chips.
+6. Resize the real Electron window to the compact desktop bounds near 960 px.
+7. Assert compact sidebar, topbar, dense assistant message, file chips, action
+   row, composer, and collapsed terminal geometry.
+8. Restore the default window size and continue the existing review, settings,
+   terminal, and commit smoke path.
+
+## Assertions
+
+- Compact viewport resolved to 960x608 content pixels.
+- Sidebar stayed compact at 236 px and topbar stayed 58 px high.
+- The dense assistant message, file chips, and action row stayed inside the
+  conversation timeline with no horizontal document overflow.
+- Required chips remained accessible: `README.md:1`,
+  `packages/desktop/src/renderer/App.tsx:12:5`, `.env.example`, `Dockerfile`,
+  `docs/guide.mdx`, and `src/App.vue`.
+- Assistant actions remained accessible: `Copy Response`, `Retry Last Prompt`,
+  and `Open Changes`.
+- Compact composer height stayed bounded at about 127 px and did not overflow
+  its context/action rows.
+- The collapsed terminal strip remained docked and closed.
+- Console errors: 0.
+- Failed local network requests: 0.
+
+## Artifacts
+
+- `compact-dense-conversation.json`
+- `compact-dense-conversation.png`
+- `compact-summary-visibility-note.json`
+- `window-resize-fallback-960x640.json`
+- `window-resize-fallback-1240x820.json`
+- `assistant-message-actions.json`
+- `assistant-message-actions.png`
+- `completed-workspace.png`
+- `electron.log`
+- `summary.json`
+
+## Known Uncovered Risk
+
+This slice covers the dense conversation and composer at compact width. A
+follow-up should add a compact-width review drawer assertion because the review
+drawer intentionally reduces conversation width.